ML19332A572

Followup to Final Deficiency Rept Re Design Inadequacy of QA Relief Valves W/Insufficient Capacity to Limit Pressure in Event of Reducing Valve Failure & Discharge Blockage.Cause Not Stated.Design Mods Underway to Replace Valves

ML19332A572
Person / Time
Site:	Fermi
Issue date:	09/05/1980
From:	Fahrner W DETROIT EDISON CO.
To:
References
10CFR-050.55E, 10CFR-50.55E, EF2-49-822, NUDOCS 8009160417
Download: ML19332A572 (3)

Text

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Detroit -

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September 5, 1980 f

EF2-49,822 5

Mr. G. Fiorelli, Chief-Reactor Construction and Engineering

, Support Branch U.S. Nuclear Regulatory Commission Region III 799 Roosev61t Road Glen Ellyn, Illinois 60137

Subject:

50.55(e) Report on RHR Heat Exchanger Relief Valve.

Dear Mr. Fiorelli:

a .

Detroit Edison has completed our investigation on the RHR Heat Exchanger Relief Valve. Our final report on this matter was submitted to you on March 2,1979. However, in a subsequent telephone conversation with your Mr. H.S. Phillips, Detroit Edison committed to a detailed review of the relief valves in the Fermi 2 systems to insure that this situation did not exist elsewhere. The results of the review are summarized below.

A design deficiency was found in the sizing of three (3) OA Level I Relief Valves;- V22-2042, V22-2045, and V22-2049. The capicities and set pres-sures of all other safety related relief valves confom with the criteria

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i of the ASME Code Section III.

• Discussion valves-V22-2042, -2045~, and -2049 are_each intended to protect piping and equipment downstream of a pressure reducing -valve. AStiE Code Section III, NC-7412 applies, which requires that the relief valve capacity be suffi-cient to limit the pressure of the low-pressure portion to 110% of design when the. reducing valve is considered to fail open and the discharge

, blocked by a closed valve. Each valve fails to meet this criteria, and may be corrected as described below:

V22-2042 (Ell-F097) - RHR HTX to RCIC Suction Presently: 10'gpm 0 415 psig set pressure Co.rrected: 500 gpm @ 125 psig The corrected capacity is the relief valve flow necessary to limit the pressure downstream of valves V8-2151 and -2152 to 110% of design under the following ' conditions:

1. 'RHR system _in steam condensing mode. 3e/7 S

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Mr. G. Fiorelli September 5, 1980 Page Two EF2-49,822

2. Control valves V8-2147 or -2148 fail open.

3. Torus line isolation valves closed.

4. RCIC pump suction or discharge valves closed.

Additionally, the present relief valve set pressure is greater than the protected boundary design pressure (125 psig).

V22-2045 (E41-F056) - HPCI Coolant Loop Presently: 10 gpm 9 125 psig set pressure Corrected: 270 gpm 9 125 psig There are no valves to block the discharge from the reducing valve. The

- corrected capacity represents the flow required to limit pressure down-stream of the reducing valve to 110% of design under the following condi-tions:

1. HPCI system in accident code A or C.

2. PCV V8-2209 fails open.

3. Lube oil cooler discharge blocked.

4. Barometric condenser effluent limited to capacity of relief valve V22-2001 (20 gpm). -

V22-2049 (E51-F018) - RCIC Coolant loop Presently: 10 gpm 0 125 psig set pressure Corrected: 90 gpm @ 125 psig Again, there are no valves to block the flow downstream of the reducing valve. The corrected capacity corresponds to the flow needed to limit the pressure downstream of the reducing valve to 110% of design under the fol-icwing conditions: ,

1. RCI system in mode A. C, or E. -

2. PCV V8-2240 fails open.

3. Barometric condenser ' effluent limited to capacity of relief valve V22-2003 (20 gpm).

Recommendations It has been determir.ed that the set pressure of valve V22-2042, and capa-cities of valves '/22-2042, -2045, and -2049 do not conform to the sizing criteria of Section III NC-7000. Design will be modified to replace the 3 valves described above, and their associated piping with the appropriate size.

Sincerely,  !

,). f -

txt. hts W.J. Fahrner, Manager Enrico Fermi 2 WJF/pn 1

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Mr. G. Fiorelli September 5, 1980 Page Three EF2-49,822 cc: Mr. Victor Stello, Jr. , Director Office of Inspection and Enforcement Division of Reactor Inspection Programs U.S. Nuclear Regulatory Commission Washington D.C. 20555 Mr. Bruce Little, Resident Inspector U.S. Nuclear Regulatory Commission Resident Inspectors Office 6450 North Dixie Highway Newport, Michigan 48166 h

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